Effect of heat treatment temperature on microstructure and properties of cold-rolled 400 series stainless steel plate

Microstructure and properties of cold-rolled ferritic stainless steel plate annealed at different temperatures (750-850 ℃) were studied.The results show that when the heat treatment temperature is below 800℃,the microstructure of the stainless steel changes little,while the strength and elongation also change not quite.At around 850℃,the grain is slightly coarsened.Ferrite and austenite two-phase structure appears during heating process.Martensite forms during the cooling of austenite,and the strength increases significantly,meanwhile,the elongation decreases drastically.Between 800℃ and 850℃,the steel can fully recrystallize,making the properties and microstructure of the steel return to the state before deformation.After annealing at 830℃,it gets the highest elongation and the grain is obviously refined.So the optimal annealing temperature is around 830℃.